NATURE 



[July 7, 19 10 



in the tropics we have diseases that can by no means 

 be considered exclusively tropical. 



Major James's work deals with smallpox in India, 

 that is, in a country, as the author bids us bear in 

 mind, where the people 



" live amid surroundings which could not be more 

 favourable to the spread of epidemic disease if 

 they had been especially devised to that end." 



In a country "where sanitation is still in its in- 

 fancy," where a continually growing proportion of the 

 population lives in the towns and cities, where there 

 is an enormous and continued extension of movement 

 among the population and of communication within 

 the country generally, where that typical " insani- 

 tary " disease, cholera, has on the whole increased, 

 and where, in spite of all this, smallpox has decreased. 

 Those who have studied the decline or disappearance 

 of smallpox in other countries know that there is one, 

 and only one, factor which could explain such a 

 phenomenon, viz. vaccination; and that vaccination is 

 the cause of the decline in India the author shows 

 in plain and easily understood language, and with 

 the aid of simple statistics that require no alleged 

 "jugglery" for their setting forth. 



Although there is a general belief that inoculation, 

 the precursor of vaccination, was in use in India from 

 time immemorial, yet the author adduces evidence 

 that in modern times, where we have trustworthy in- 

 formation, it was entirely unknown in certain 

 provinces, but he does not suggest any explanation 

 of this curious discrepancy. Where inoculation was 

 practised it was apparently done with marked success, 

 but the regulations attending if were strict. At a 

 later period, when irregularities in the practice arose, 

 it became one of considerable danger, and was gradu- 

 ally superseded by the introduction of vaccination. 



In chapter iii. is given a short account of the origin 

 of vaccination from the first introduction of human 

 vaccine threads into India in 1902 down to the use 

 of calf lymph at the present day. It is interesting to 

 note the opposition to vaccination in Bengal, as a 

 few years ago the writer experienced there perfectly 

 irrational opposition to the making of linger-pricks 

 for simple blood examinations. 



The following simple tables will suffice to give an 

 idea of how smallpox had decreased from periods in 

 which there was "less" vaccination to those in which 

 there was "more," but to be fully appreciated the 

 original data in Major James's book should be con- 

 sulted. 



iBOB-lSSy 1888-IQ07 

 Smalliiox d^ath- Smallpox death- 

 rate per miUion rata per million 

 o( populatijn of population 



537'2 240-5 



1 020 • I 5027 



1099-3 520-7 



1163-9 673-0 



1083-1 1S3-0 



Bombay 



Cenlrdl Provincei 



Punjab 



Madras 



Bcrar 



Biilish India as a whole 1032-3 466-0 



If these latter figures are compared with the chart 

 of the total number of vaccinations performed in 

 British India, it will be seen at once that the fall in 

 smallpox mortality coincides with the rise of vaccina- 

 tion. 



Another method which is independent of statistics 

 NO. 2123, VOL. 84] 



of population is to consider the proportion which 

 smallpox deaths bear to the total deaths from all 

 causes in two periods, one with "less" and the other 

 with "more" vaccination. If an "epidemic" is now 

 arbitrarily defined as one in which the deaths from 

 smallpox form 5 or more per cent, of the deaths 

 from all causes, we get the following data here put in 

 tabular form : — 



1868-1887 i88S-ig07 



No. of epiden.ics No. of epidemics 



Cential Provinces 5 ° 



Punjab 7 ° 



Biitish India as a whole ... 9 o 



Another interesting observation is that prior to 1886 

 the attack rate among natives was always greater than 

 among the European troops, but that after this date 

 the position was reversed. The explanation given by 

 the author is that since 1885 vaccination and success- 

 ful re-vaccination have been less carefully attended to 

 among Europeans than among native troops, and 

 figures are given showing that among Europeans in 

 1906 there v.-ere more than 20,000 individuals without 

 any marks or record of vaccination — a sufficiently lax 

 condition of affairs— but the proof to be complete 

 should have given the corresponding figures for the 

 native troops. Another very interesting table is that 

 showing the constantly greater incidence of smallpox 

 among the wives of European soldiers than among 

 the men, while as regards cholera and enteric fever 

 Ihe reverse is the case. The difference is due, no 

 doubt, as the author points out, to the almost total 

 absence of successful re-vaccination among the 

 women. To the table there should, we think, have 

 been added the "strength" of the women. 



Other equally convincing tables are given, in- 

 variably pointing to some factor (vaccination) in- 

 fluencing the figures in the same direction ; the tables, 

 moreover, have the merit of being simple, though, as 

 the author points out, if subjected to analysis they 

 would be even more convincing, if that were neces- 

 sary. 



The laborious task the author set himself has been 

 well done. We are not aware what steps are taken 

 in India to explain the merits of vaccination to the 

 people, but nothing could do so better than this book. 

 01 a short digest of it if that be possible. 



THE ALTERNATE-CURRENT THEORY. 

 The Foundations of Alternate Current Theory. By 

 Dr. C. V. Drysdale. Pp. xi-l-300. (London : 

 Edward Arnold, 1910.) Price Ss. 6d. net. 



IN English text-books on electrical engineering one 

 finds occasionally an attempt to elucidate some 

 property of an electric circuit by a mechanical mode!. 

 A favourite analogy is a water-tank with pipe and 

 .stop-cock. The head of water represents E.iM.F., the 

 pipe takes the place of the conductor, the stop-cock 

 that of the switch, and the flow of water represents 

 the current. Also, a railway waggon with buffer- 

 springs is often used to explain inductance and capa- 

 city. These analogies are, however, only used as 

 additional explanations of a theory built up inde- 

 pendently of them. In the present book they are the 

 tlieory itself, or rather the foundation on which the 

 author builds up the theory of alternating-current 



